Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Review Article
  • Published:

The emergence of perovskite solar cells

Abstract

The past two years have seen the unprecedentedly rapid emergence of a new class of solar cell based on mixed organic–inorganic halide perovskites. Although the first efficient solid-state perovskite cells were reported only in mid-2012, extremely rapid progress was made during 2013 with energy conversion efficiencies reaching a confirmed 16.2% at the end of the year. This increased to a confirmed efficiency of 17.9% in early 2014, with unconfirmed values as high as 19.3% claimed. Moreover, a broad range of different fabrication approaches and device concepts is represented among the highest performing devices — this diversity suggests that performance is still far from fully optimized. This Review briefly outlines notable achievements to date, describes the unique attributes of these perovskites leading to their rapid emergence and discusses challenges facing the successful development and commercialization of perovskite solar cells.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Perovskite crystal structure and associated tolerance and octahedral factors.
Figure 2: Perovskite cell structure and associated vacuum energy levels.
Figure 3: Absorption coefficients and relative permittivity.
Figure 4: Electron-transfer processes in nanoparticle and bulk cells together with a bulk energy-band diagram.

Similar content being viewed by others

References

  1. Turner, G. Global Renewable Energy Market Outlook 2013. Bloomberg New Energy Finance https://www.bnef.com/insightdownload/7526/pdf (11 April 2014).

    Google Scholar 

  2. Park, N.-G. Organometal perovskite light absorbers toward a 20% efficiency low-cost solid-state mesoscopic solar cell. J. Phys. Chem. Lett. 4, 2423–2429 (2013).

    Article  Google Scholar 

  3. Snaith, H. J. Perovskites: the emergence of a new era for low-cost, high-efficiency solar cells. J. Phys. Chem. Lett. 4, 3623–3630 (2013).

    Article  Google Scholar 

  4. Kim, H.-S., Im, S. H. & Park, N.-G. Organolead halide perovskite: new horizons in solar cell research. J. Phys. Chem. C 118, 5615–5625 (2014).

    Article  Google Scholar 

  5. Hodes, G. & Cahen, D. Photovoltaics: perovskite cells roll forward. Nature Photon. 8, 87–88 (2014).

    Article  ADS  Google Scholar 

  6. Service, R. F. Perovskite solar cells keep on surging. Science 344, 458 (2014).

    Article  ADS  Google Scholar 

  7. Li, C. et al. Formability of ABX3 (X = F, Cl, Br, I) halide perovskites. Acta Crystallogr. B 64, 702–707 (2008).

    Article  Google Scholar 

  8. McKinnon, N. K., Reeves, D. C. & Akabas, M. H. 5-HT3 receptor ion size selectivity is a property of the transmembrane channel, not the cytoplasmic vestibule portals. J. Gen. Physiol. 138, 453–466 (2011).

    Article  Google Scholar 

  9. Cohen, B. N., Labarca, C., Davidson, N. & Lester, H. A. Mutations in M2 alter the selectivity of the mouse nicotinic acetylcholine receptor for organic and alkali metal cations. J. Gen. Physiol. 100, 373–400 (1992).

    Article  Google Scholar 

  10. Im, J.-H., Chung, J., Kim, S.-J. & Park, N.-G. Synthesis, structure, and photovoltaic property of a nanocrystalline 2H perovskite-type novel sensitizer (CH3CH2NH3)Pbl3 . Nanoscale Res. Lett. 7, 353 (2012).

    Article  ADS  Google Scholar 

  11. Koh, T. M. et al. Formamidinium-containing metal-halide: an alternative material for near-IR absorption perovskite solar cells. J. Phys. Chem. C http://dx.doi.org/10.1021/jp411112k (13 December 2013).

  12. Eperon, G. E. et al. Formamidinium lead trihalide: a broadly tunable perovskite for efficient planar heterojunction solar cells. Energy Environ. Sci. 7, 982–988 (2014).

    Article  Google Scholar 

  13. Pang, S. et al. NH2CH=NH2Pbl3: An alternative organolead iodide perovskite sensitizer for mesoscopic solar cells. Chem. Mater. 26, 1485–1491 (2014).

    Article  ADS  Google Scholar 

  14. Umari, P., Mosconi, E. & De Angelis, F. Relativistic GW calculations on CH3NH3PbI3 and CH3NH3SnI3 perovskites for solar cell applications. Sci. Rep. 4, 4467 (2014).

    Article  ADS  Google Scholar 

  15. Topsöe, H. Krystallographisch-chemische untersuchungen homologer verbindungen. Zeitschrift für Kristallographie 8, 246–296 (1884).

    Google Scholar 

  16. Mitzi, D. B., Wang, S., Feild, C. A., Chess, C. A. & Guloy, A. M. Conducting layered organic–inorganic halides containing <110>-oriented perovskite sheets. Science 267, 1473–1476 (1995).

    Article  ADS  Google Scholar 

  17. Mitzi, D. B., Chondroudis, K. & Kagan, C. R. Organic-inorganic electronics. IBM J. Res. Dev. 45, 29–45 (2001).

    Article  Google Scholar 

  18. Kojima, A., Teshima, K., Miyasaka, T. & Shirai, Y. Novel photoelectrochemical cell with mesoscopic electrodes sensitized by lead-halide compounds (2). in Proc. 210th ECS Meeting (ECS, 2006).

    Google Scholar 

  19. Kojima, A., Teshima, K., Shirai, Y. & Miyasaka, T. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc. 131, 6050–6051 (2009).

    Article  Google Scholar 

  20. Kojima, A., Teshima, K., Shirai, Y. & Miyasaka, T. Novel photoelectrochemical cell with mesoscopic electrodes sensitized by lead-halide compounds (11). in Proc. 214th ECS Meeting (ECS, 2014).

    Google Scholar 

  21. Im, J.-H., Lee, C.-R., Lee, J.-W., Park, S.-W. & Park, N.-G. 6.5% efficient perovskite quantum-dot-sensitized solar cell. Nanoscale 3, 4088–4093 (2011).

    Article  ADS  Google Scholar 

  22. Kim, H.-S. et al. Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%. Sci. Rep. 2, 591 (2012).

    Article  Google Scholar 

  23. Lee, M. M., Teuscher, J., Miyasaka, T., Murakami, T. N. & Snaith, H. J. Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites. Science 338, 643–647 (2012).

    Article  ADS  Google Scholar 

  24. Salbeck, J., Yu, N., Bauer, J., Weissörtel, F. & Bestgen, H. Low molecular organic glasses for blue electroluminescence. Synthetic Metals 91, 209–215 (1997).

    Article  Google Scholar 

  25. Bach, U. et al. Solid-state dye-sensitized mesoporous TiO2 solar cells with high photon-to-electron conversion efficiencies. Nature 395, 583–585 (1998).

    Article  ADS  Google Scholar 

  26. Stranks, S. D. et al. Electron–hole diffusion lengths exceeding 1 micrometer in an organometal trihalide perovskite absorber. Science 342, 341–344 (2013).

    Article  ADS  Google Scholar 

  27. Heo, J. H. et al. Efficient inorganic–organic hybrid heterojunction solar cells containing perovskite compound and polymeric hole conductors. Nature Photon. 7, 486–491 (2013).

    Article  ADS  Google Scholar 

  28. Noh, J. H, Im, S. H., Heo, J. H., Mandal, T. N. & Seok, S. I. Chemical management for colorful, efficient, and stable inorganic-organic hybrid nanostructured solar cells. Nano Lett. 13, 1764–1769 (2013).

    Article  ADS  Google Scholar 

  29. Stoumpos, C. C., Malliakas, C. D. & Kanatzidis, M. G. Semiconducting tin and lead iodide perovskites with organic cations: phase transitions, high mobilities, and near-infrared photoluminescent properties. Inorg. Chem. 52, 9019–9038 (2013).

    Article  Google Scholar 

  30. Burschka, J. et al. Sequential deposition as a route to high-performance perovskite-sensitized solar cells. Nature 499, 316–319 (2013).

    Article  ADS  Google Scholar 

  31. Green, M. A., Emery, K., Hishikawa, Y., Warta, W. & Dunlop, E. D. Solar cell efficiency tables (version 43). Prog. Photovolt. 22, 1–9 (2014).

    Article  Google Scholar 

  32. Liu, M., Johnston, M. B. & Snaith, H. J. Efficient planar heterojunction perovskite solar cells by vapour deposition. Nature 501, 395–398 (2013).

    Article  ADS  Google Scholar 

  33. Burschka, J. High performance solid-state mesoscopic solar cells. PhD thesis, École Polytechnique Fédérale de Lausanne 107 (2013).

  34. Chen, Q. et al. Planar heterojunction perovskite solar cells via vapor-assisted solution process. J. Am. Chem. Soc. 136, 622–625 (2014).

    Article  Google Scholar 

  35. Liu, D. & Kelly, T. L. Perovskite solar cells with a planar heterojunction structure prepared using room-temperature solution processing techniques. Nature Photon. 8, 133–138 (2014).

    Article  ADS  Google Scholar 

  36. Christians, J. A., Fung, R. C. M. & Kamat, P. V. An inorganic hole conductor for organo-lead halide perovskite solar cells. Improved hole conductivity with copper iodide. J. Am. Chem. Soc. 136, 758–764 (2014).

    Article  Google Scholar 

  37. Ito, S. Pb perovskite solar cells using inorganic hole conductor of CuSCN. Paper Y-RS-14 in 2013 MRS Fall Meeting & Exhibit (MRS, 2013).

    Google Scholar 

  38. Docampo, P., Ball, J. M., Darwich, M., Eperon, G. E. & Snaith, H. J. Efficient organometal trihalide perovskite planar-heterojunction solar cells on flexible polymer substrates. Nature Commun. 4, 2761 (2013).

    Article  ADS  Google Scholar 

  39. Malinkiewicz, O. et al. Perovskite solar cells employing organic charge-transport layers. Nature Photon. 8, 128–132 (2014).

    Article  ADS  Google Scholar 

  40. Sun, S. et al. The origin of high efficiency in low-temperature solution-processable bilayer organometal halide hybrid solar cells. Energy Environ. Sci. 7, 399–407 (2014).

    Article  Google Scholar 

  41. Wang, J. T.-W. et al. Low-temperature processed electron collection layers of graphene/TiO2 nanocomposites in thin film perovskite solar cells. Nano Lett. 14, 724–730 (2014).

    Article  ADS  Google Scholar 

  42. Wojciechowski, K., Saliba, M., Leijtens, T., Abate, A. & Snaith, H. J. Sub-150 °C processed meso-superstructured perovskite solar cells with enhanced efficiency. Energy Environ. Sci. 7, 1142–1147 (2014).

    Article  Google Scholar 

  43. Eperon, G. E., Burlakov, V. M., Goriely, A. & Snaith, H. J. Neutral color semitransparent microstructured perovskite solar cells. ACS Nano 8, 591–598 (2014).

    Article  Google Scholar 

  44. Wang, J. et al. Performance improvement of amorphous silicon see-through solar modules with high transparency by the multi-line ns-laser scribing technique. Opt. Las. Eng. 51, 1206–1212 (2013).

    Article  Google Scholar 

  45. Even, J., Pedesseau, L., Jancu, J.-M. & Katan, C. Importance of spin-orbit coupling in hybrid organic/inorganic perovskites for photovoltaic applications. J. Phys. Chem. Lett. 4, 2999–3005 (2013).

    Article  Google Scholar 

  46. Sell, D. D. & Lawaetz, P. New analysis of direct exciton transitions: application to GaP. Phys. Rev. Lett. 26, 311–314 (1971).

    Article  ADS  Google Scholar 

  47. Even, J., Pedesseau, L., Dupertuis, M.-A., Jancu, J.-M. & Katan, C. Electronic model for self-assembled hybrid organic/perovskite semiconductors: reverse band edge electronic states ordering and spin-orbit coupling. Phys. Rev. B 86, 205301 (2012).

    Article  ADS  Google Scholar 

  48. Ishihara, T. Optical properties of PbI-based perovskite structures. J. Luminescence 60, 269–274 (1994).

    Article  ADS  Google Scholar 

  49. D'Innocenzo, V. et al. Excitons versus free charges in organo-lead tri-halide perovskites. Nature Commun. 5, 3586 10.1038/ncomms4586(2014).

    Article  ADS  Google Scholar 

  50. Tauc, J. Optical properties and electronic structure of amorphous Ge and Si. Mater. Res. Bull. 3, 37–46 (1968).

    Article  Google Scholar 

  51. Elliott, R. J. Intensity of optical absorption by excitons. Phys. Rev. 108, 1384–1389 (1957).

    Article  ADS  Google Scholar 

  52. Tanaka, K. et al. Comparative study on the excitons in lead-halide-based perovskite-type crystals CH3NH3PbBr3 CH3NH3PbI3 . Solid State Commun. 127, 619–623 (2003).

    Article  ADS  Google Scholar 

  53. Combescot, M. Thermodynamics of an electron-hole system in semiconductors. Phys. Status Solidi B 86, 349–358 (1978).

    Article  ADS  Google Scholar 

  54. Corkish, R., Chan, D. S.-P. & Green, M. A. Excitons in silicon diodes and solar cells: a three-particle theory. J. Appl. Phys. 79, 195–203 (1996).

    Article  ADS  Google Scholar 

  55. Geelhaar, F. Coulomb Correlation Effects in Silicon Devices (Series in Microelectronics 147 Hartung-Gorre, 2004).

    Google Scholar 

  56. Green, M. A. Many-body theory applied to solar cells: excitonic and related carrier correlation effects in Proc. 26th IEEE Photovoltaic Specialists Conference (1997).

    Google Scholar 

  57. Green, M. A. Radiative efficiency of state-of-the-art photovoltaic cells. Prog. Photovolt. 20, 472–476 (2012).

    Article  Google Scholar 

  58. Ungár, T. The meaning of size obtained from broadened X-ray diffraction peaks. Adv. Eng. Mater. 5, 323–329 (2003).

    Article  Google Scholar 

  59. Edalati, K. & Horita, Z. Significance of homologous temperature in softening behavior and grain size of pure metals processed by high-pressure torsion. Mater. Sci. Eng. A 528, 7514–7523 (2011).

    Google Scholar 

  60. Edri, E. et al. Why lead methylammonium tri-iodide perovskite-based solar cells require a mesoporous electron transporting scaffold (but not necessarily a hole conductor). Nano Lett. 14, 1000–1004 (2014).

    Article  ADS  Google Scholar 

  61. Liang, K., Mitzi D. B. & Prikas, M. T. Synthesis and characterization of organic–inorganic perovskite thin films prepared using a versatile two-step dipping technique. Chem. Mater. 10, 403–411 (1998).

    Article  Google Scholar 

  62. Kim, J., Lee, S.-H., Lee, J. H. & Hong, K.-H. The role of intrinsic defects in methylammonium lead iodide perovskite. J. Phys. Chem. Lett. 5, 1312–1317 (2014).

    Article  Google Scholar 

  63. Yin, W.-J., Shi, T. & Yan, Y. Unusual defect physics in CH3NH3PbI3 perovskite solar cell absorber. Appl. Phys. Lett. 104, 063903 (2014).

    Article  ADS  Google Scholar 

  64. Onoda-Yamamuro, N., Matsuo, T. & Suga, H. Dielectric study of CH3NH3PbX3 (X = Cl, Br, I). J. Phys. Chem. Solids 53, 935–939 (1992).

    Article  ADS  Google Scholar 

  65. Poglitsch, A. & Weber, D. Dynamic disorder in methylammoniumtrihalogenoplumbates (II) observed by millimeter-wave spectroscopy. J. Chem. Phys. 87, 6373 (1987).

    Article  ADS  Google Scholar 

  66. Hirasawa, M., Ishihara, T., Goto, T., Uchida, K. & Miura, N. Magnetoabsorption of the lowest exciton in perovskite-type compound (CH3NH3)PbI3 . Physica B 201, 427–430 (1994).

    Article  ADS  Google Scholar 

  67. Yuan, Y., Xiao, Z., Yang, B. & Huang, J. Arising applications of ferroelectric materials in photovoltaic devices. J. Mater. Chem. A 2, 6027–6041 (2014).

    Article  Google Scholar 

  68. Frost, J. M. et al. Atomistic origins of high-performance in hybrid halide perovskite solar cells. Nano Lett. 14, 2584–2590 (2014).

    Article  ADS  Google Scholar 

  69. Snaith, H. J. et al. Anomalous hysteresis in perovskite solar cells. J. Phys. Chem. Lett. 5, 1511–1515 (2014).

    Article  Google Scholar 

  70. Hoke, E. T., Unger, E. L., Vandewal, K. & McGehee, M. D. Charge recombination and transport in hybrid perovskite solar cells: why do perovskite solar cells have large Voc? in Proc. MRS Fall Meeting and Exhibit (2013).

    Google Scholar 

  71. Marchioro, A. et al. Unravelling the mechanism of photoinduced charge transfer processes in lead iodide perovskite solar cells. Nature Photon. 8, 250–255 (2014).

    Article  ADS  Google Scholar 

  72. Edri, E. et al. Elucidating the charge carrier separation mechanism in CH3NH3PbI3-xClx perovskite solar cells. Nature Commun. 5, 3461 (2014).

    Article  ADS  Google Scholar 

  73. Stranks, S. D. et al. Electron–hole diffusion lengths exceeding 1 micrometer in an organometal trihalide perovskite absorber. Science 342, 341–344 (2013).

    Article  ADS  Google Scholar 

  74. Xing, G. et al. Long-range balanced electron- and hole-transport lengths in organic–inorganic CH3NH3Pbl3 . Science 342, 344–347 (2013).

    Article  ADS  Google Scholar 

  75. Anderson, R. L. Germanium-gallium arsenide heterojunction. IBM J. Res. Dev. 4, 283–287 (1960).

    Article  Google Scholar 

  76. Peressi, M., Baldereschi, A. & Baroni, S. in Characterization of Semiconductor Heterostructures and Nanostructures 2nd Edn (eds Agostini G. & Lamberti, C) Ch. 2 (Elsevier, 2008).

    Google Scholar 

  77. Kavan, L. & Grätzel, M. Highly efficient semiconducting TiO2 photoelectrodes prepared by aerosol pyrolysis. Electrochimica Acta 40, 643–652 (1995).

    Article  Google Scholar 

  78. Green, M. A. The depletion layer collection efficiency for p-n junction, Schottky diode, and surface insulator solar cells. J. Appl. Phys. 47, 547–554 (1976).

    Article  ADS  Google Scholar 

  79. Lindblad, R. et al. Electronic structure of TiO2/CH3NH3PbI3 perovskite solar cell interfaces. J. Phys. Chem. Lett. 5, 648–653 (2014).

    Article  Google Scholar 

  80. Schulz, P. et al. Interface energetics in organo-metal halide perovskite-based photovoltaic cells. Energy Environ. Sci. 7, 1377–1381 (2014).

    Article  Google Scholar 

  81. First Solar Sets New World Record for CdTe Solar Cell Efficiency. http://investor.firstsolar.com/releasedetail.cfm?releaseid=743398 (26 February 2013).

  82. Widmar, M. First Solar Q4′13 Earnings Call. http://files.shareholder.com/downloads/fslr/1347979521x0x728649/bddfd430-a025-43e4-8b91-c1915066b274/q413_earnings_call_presentation_final1.pdf (25 February 2014).

    Google Scholar 

  83. De Jong, T. First Solar Manufacturing Update. http://files.shareholder.com/downloads/fslr/3084163747x0x652323/53f7a04f-fcf5-4729-8bb2-0abf6033c046/4.%20fsanalystday_manufacturing.pdf (11 April 2014).

    Google Scholar 

  84. Garabedian, R. Technology Update. 2013 Analyst Meeting, First Solar. http://files.shareholder.com/downloads/FSLR/3084163747x0x652328/d0af6554-e193-47e4-9dd0-59b02968272b/fsanalystday_technologyupdate.pdf (11 April 2014).

    Google Scholar 

  85. Rinaldi, N. Solar PV Module Costs to Fall to 36 Cents per Watt by 2017 http://www.greentechmedia.com/articles/read/solar-pv-module-costs-to-fall-to-36-cents-per-watt (18 June 2013).

    Google Scholar 

  86. Directive 2011/65/EU of the European Parliament and of the Council of 8 June 2011 on the restriction of the use of certain hazardous substances in electrical and electronic equipment (recast). http://eur-lex.europa.eu/legal-content/en/TXT/?uri=celex:32011L0065 (8 June 2011).

  87. Coyle, D. J. Life prediction for CIGS solar modules part 1: modeling moisture ingress and degradation. Prog. Photovolt. 21, 156–172 (2013).

    Article  Google Scholar 

  88. Coyle, D. J. et al. Life prediction for CIGS solar modules part 2: degradation kinetics, accelerated testing, and encapsulant effects. Prog. Photovolt. 21, 173–186 (2013).

    Article  Google Scholar 

  89. Kempe, M. D., Dameron, A. A. & Reese, M. O. Evaluation of moisture ingress from the perimeter of photovoltaic modules. Prog. Photovolt. http://dx.doi.org/10.1002/pip.2374 (2013).

  90. Kempe, M. D., Panchagade, D., Reese, M. O. & Dameron, A. A. Modeling moisture ingress through polyisobutylene-based edge-seals. Prog. Photovolt. http://dx.doi.org/10.1002/pip.2465 (2014).

  91. Niu, G. et al. Study on the stability of CH3NH3PbI3 films and the effect of post-modification by aluminum oxide in all-solid-state hybrid solar cells. J. Mater. Chem. A 2, 705–710 (2014).

    Article  Google Scholar 

  92. Carcia, P. F., McLean, R. S. & Hegedus, S. ALD Moisture barrier for Cu(InGa)Se2 solar cells. in Proc. 218th ECS Meeting (ECS, 2010).

    Google Scholar 

  93. Leijtens, T. et al. Overcoming ultraviolet light instability of sensitized TiO2 with meso-superstructured organometal tri-halide perovskite solar cells. Nature Commun. 4, 2885 (2013).

    Article  ADS  Google Scholar 

  94. Werner, J. H., Zapf-Gottwick, R., Koch, M. & Fischer, K. Toxic substances in photovoltaic modules. in Proc. 21st Int. Photovoltaic Sci. Eng. Conf. (2011).

    Google Scholar 

  95. Noel, N. K. et al. Lead-free organic-inorganic tin halide perovskites for photovoltaic applications. Energy Environ. Sci. http://dx.doi.org/10.1039/c4ee01076K (2014).

  96. Wehrenfennig, C., Liu, M., Snaith, H. J., Johnston, M. B. & Herz, L. M. Homogeneous emission line broadening in the organo lead halide perovskite CH3NH3PbI3-xClx . J. Phys. Chem. Lett. 5, 1300–1306 (2014).

    Article  Google Scholar 

  97. Rühle, S. & Dittrich, T. Investigation of the electric field in TiO2/FTO junctions used in dye-sensitized solar cells by photocurrent transients. J. Phys. Chem. B 109, 9522–9526 (2005).

    Article  Google Scholar 

  98. Snaith, H. J. & Grätzel, M. The role of a “Schottky barrier” at an electron-collection electrode in solid-state dye-sensitized solar cells. Adv. Mater. 18, 1910–1914 (2006).

    Article  Google Scholar 

  99. Kron, G., Rau, U. & Werner, J. H. Influence of the built-in voltage on the fill factor of dye-sensitized solar cells. J. Phys. Chem. B 107, 13258–13261 (2003).

    Article  Google Scholar 

Download references

Acknowledgements

The Australian Centre for Advanced Photonics (ACAP) is supported by the Australian Government through the Australian Renewable Energy Agency (ARENA). Responsibility for the views, information or advice expressed herein is not accepted by the Australian Government. H.J.S. is supported by the Engineering and Physical Sciences Research Council UK and the European Research Council.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Martin A. Green.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Green, M., Ho-Baillie, A. & Snaith, H. The emergence of perovskite solar cells. Nature Photon 8, 506–514 (2014). https://doi.org/10.1038/nphoton.2014.134

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nphoton.2014.134

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing